Chandrayaan-3 countdown progressing well: ISRO

With just a few hours to go for the Chandrayaan-3 launch, the Indian Space Research Organisation (ISRO) on Friday said the 25-hour and 30-minute countdown for the ambitious mission was progressing with the completion of propellant filling in the L110 stage and commencing of propellant filling in the C25 stage.

The countdown started on Thursday afternoon, a day after the mission readiness review was completed following which the board authorised the launch for 2.35 pm on Friday. Scientists at the Sathish Dhawan Space Centre (SDSC) in Sriharikota and ISRO headquarters in Bengaluru are working round-the-clock to ensure that Friday’s launch is successful.

“The countdown is progressing at SDSC-SHAR, Sriharikota. Propellant filling in the L110 stage is completed. Propellant filling in the C25 stage is commencing,” the ISRO said in a brief update Friday morning, as hundreds of students and the public began arriving at Sriharikota to witness the historic launch.

The SDSC was teeming with school students, space enthusiasts, and people from near Sriharikota on Friday morning, even as the security was beefed-up. As the launch is scheduled for 2.35 pm, authorities have asked fishermen to refrain from fishing in the Pullicat Lake area in Tamil Nadu and Andhra Pradesh.

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ISRO chairman S Somnath, his predecessors, including K Sivan who oversaw the launch of the Chandrayaan-2, and scientists who worked on the project will witness the launch from the Mission Control Room. The primary aim of India’s third unmanned lunar mission, Chandrayaan-3, is to explore the south-polar region of the moon by making a soft and safe landing on the lunar surface.

If the mission is successful, India will only be the fourth country to have achieved the feat, joining the elite club of the US, Russia, and China. The south-polar region of the moon is of intense interest due to the presence of many permanently shadowed craters which could contain water ice and precious minerals.

At the end of the 25-hour and 30-minute countdown, LVM3-M4, India’s largest and heaviest launch vehicle, LVM3-M4, will lift off at 2:35 pm with the 3,900-kg Chandrayaan-3 spacecraft, including the lander. Minutes later, it will transfer the satellites into the Geo Transfer orbit.

Billed as a follow-up mission to Chandrayaan-2 which failed after the lander crash-landed on the moon 48 days later, Chandrayaan-3 will seek to demonstrate end-to-end landing and roving capabilities. The spacecraft will take about 40 days to make a soft landing on the lunar surface which is expected to be between August 23 and 24, eight days lesser than what the Chandrayaan-2 mission took.

The success of Chandrayaan-3 will also help the ISRO fast-tracking its planned manned mission to the space, named Gaganyaan.

The Chandrayaan-3 mission is yet another attempt to achieve the goal with the help of a rover. The spacecraft, according to officials, will have four payloads which will study moon quakes, as to how the surface of the moon allows heat to flow through it, the plasma environment near the moon's surface, and enable scientists to measure the distance between Earth and moon “very accurately.”

The two rover payloads study composition of the moon’s surface using X-rays and LASER, while the propulsion module payload will explore the Spectro-polarimetric signatures of the habitable planet, Earth. The mission is divided into three phases -- Earth Centric, Lunar Transfer, and Moon Centric.